To Fritz Müller   23 August [1866]1

Down. | Bromley. | Kent. S.E.

Aug 23

My dear Sir

I have been very neglectful in not having thanked you sooner for your valuable letter of June 1st, but I have rather more work to do than I can manage & so my correspondence suffers.2

Many of the facts which you mention are very curious & interesting, & if ever I publish a supplement to my Orchis book I shall make use of some of them.3 I am much surprized at what you say about those with large flowers seeding so badly.4 I am especially interested in the case of one of the Epidendreæ which has pollinia for removal by insects & others for self-fertilization.5

Your letter with its elegant drawings & dried flowers is quite a pretty object. The case of the Bourlingtonia is entirely new.6 As for the course of the vessels in the various organs of the flower I dare say your interpretation may be right, & I have little doubt that mine was wrong.7

I am glad to say that I received the other day a proof of your paper on climbing plants, & when I receive copies I will send one for the Bot. Zeitung, another for the American Journ. of Science, another to the Soc. Bot. of Paris & retain one for myself, sending the remainder to you.8

You will receive at about the same time with this note a copy of the new Ed. of the Origin.9 I do not know how much you attend to plants but if it wd be of much service to you, I should be happy to send you the two parts as yet published of “Bentham & Hookers Genera Plantarum”, for I have often thought of buying a second copy for the sake of adding to the sale,—which has been small.10

Have you seen Prof. Claus recent pamphlet on Copepoda in which he treats of their individual variability:11 he speaks most respectfully of your work, but seems to feel some doubt with respect to the two forms of Orchestia.12

With every good wish & sincere respect Pray believe me yours very faithfully | Charles Darwin

P.S. I have forgotten to thank you for the beautiful drawing of the Vanilla-like plant.13

LS(A)

1
The year is established by the reference to receiving a proof copy of Müller’s paper on climbing plants (see n. 8, below).
2
Müller’s letter of 1 June 1866 has not been found.
3
CD mentioned several of Müller’s observations in ‘Fertilization of orchids’ and Orchids 2d ed.
4
No other mention has been found of large flowers of orchids seeding badly.
5
See letter from Fritz Müller, 2 August 1866 and nn. 3 and 5. In F. Müller 1869, p. 226, Müller noted that in this unnamed species of Epidendrum, the two anthers located on either side of the middle anther were for self-fertilisation while the middle anther had pollinia that could only be removed by insects. CD mentioned the additional anthers for self-fertilisation in Orchids 2d ed., p. 291.
6
None of the drawings or dried flowers that Müller enclosed with the letter of 1 June 1866 has been found. In a letter to Müller of [9 and] 15 April [1866], CD had suggested that Müller should ‘observe any cases of flowers which catch insects by their probosces’. Müller’s remarks about Burlingtonia may have concerned his observation of two fork-like projections of the pistil reaching over the stigma, which, he explained, served to detach pollen from the proboscis of an insect visiting the flower and deposit it into the stigmatic cavity. Müller later mentioned the phenomenon in a letter to his brother, Hermann, of 30 May 1867 (see Möller ed. 1915–21, 2: 123–7; a diagram made by Müller in May 1866 of the stigmatic projections of Burlingtonia is on p. 125). In Orchids, pp. 182–94, CD had discussed the movement of the pedicel (‘stipe’ in modern orchid terminology; see Dressler 1981, pp. 61–2) as an aid to pollination in various genera of the orchid tribe Vandeae, including two species of Rodriguezia (Rodriguezia is a synonym for Burlingtonia). He had not observed the projections that Müller described. Müller had noted the elastic pedicel but observed that in his specimen the stigma was not capable of detaching a pollen-mass owing to its weakly adhesive surface, but that the fork-like projections, by grasping the pollen-masses from an insect’s proboscis above the stigmatic cavity, detached them and deposited them on the stigma (Möller ed. 1915–21, p. 125).
7
CD is probably referring to Müller’s description of a Vanilla-like flower with two rudimentary stamens in the outer whorl (see letter to Fritz Müller, 23 May 1866 and nn. 2 and 3). CD’s interpretation of the labellum as a compound structure made up of a petal and two sterile petaloid stamens (Orchids, p. 294) was cast into doubt by this observation, but he maintained his view of the nature of the labellum (see Orchids 2d ed., p. 238; for a modern assessment of the structure of the labellum, see Dressler 1981, pp. 43–4).
8
The reference is to F. Müller 1865b, which appeared in the 29 November 1866 issue of the Journal of the Linnean Society (Botany) (see letter from Frederick Currey, 5 July 1866 and n. 1). The other journals to which CD refers are the Botanische Zeitung, the American Journal of Science and Arts, and the Bulletin de la Société Botanique de France, which published a notice of F. Müller 1865b (Bulletin de la Société Botanique de France 14 (1867): 70–1).
9
Although the fourth edition of Origin was printed by mid July 1866, the publisher, John Murray, did not release it for sale until November 1866; however, Murray agreed to send presentation copies to selected recipients before publication (see letter to John Murray, 15 July [1866] and n. 3, and letter from John Murray, 18 July [1866]). Müller’s name is on CD’s presentation list for the fourth edition of Origin (Correspondence vol. 14, Appendix IV).
10
Bentham and Hooker 1862–83 was published in seven parts. The first two parts appeared in 1862 and 1865. CD’s complete set is in the Darwin Library–CUL.
11
CD refers to Carl Friedrich Claus’s monograph on the copepods of Nice (Claus 1866). CD had commented on the book to several correspondents (see second postscript to letter to J. D. Hooker, 3 and 4 August [1866], letter to Ernst Haeckel, 18 August [1866], and letter to B. D. Walsh, 20 August [1866]).
12
Claus praised Müller’s book, Für Darwin (F. Müller 1864c), referring to it as excellent, full of noteworthy observations and remarkable facts. While Claus agreed in principle with the possibility of two forms of males having come about as a result of different environmental pressures, in the case of Orchestia he questioned whether one might be the sexually mature form of the other, as was the case with another amphipod, Phronima (see Claus 1866, pp. 1 and 2; see also F. Müller 1864c, pp. 16–17).
13
The drawing referred to was probably one sent with the letter from Fritz Müller, 3 April 1866. Neither the letter nor the drawing has been found. It is possible that CD returned the drawing (see letter to Fritz Müller, 23 May 1866 and nn. 2 and 4).

Manuscript Alterations and Comments

2.5 by insects] interl in CD’s hand

Please cite as “DCP-LETT-5196,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-5196